Spark-testing device for gasoline engines



l w. P. MOTT: SPARK TESTING DEVICE FOR `GASOLINI' ENGINES. APPLICATION FILED MAR.29, |919.

1,542,622@ l y 'I Pat@nteaJu1y25,1922.

usara sraras WILLIAM P. IvIGTT, OF CHICAGO, ILLINOIS.

spank-TESTING nnvrcn ron easorirnn ENGINES.

Specification of Letters Patent. i

Pa'entcd l uly .25, 151252.

Application mea-March es, 1919. serial no. 286,097.

-To all whom t may conce/rn.'

Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Spark-Testing Devices for Gasoline Engines, oit winch the following is a specification.

This invention relates to a spark testing device for gasoline engines, and its purpose is to provide improved means lor determining whether explosions areoccurring regularly in all of the cylinders of a gasoline engine or whether sparks -are passing between the terminals of the various spark plugs. The principal object ot' the invention is to provide a simple and eflicient testing switch which may be inserted in the circuit ot the spark plug and opened when desired to determine whether the circuit is being completed through the spark plug. This testing switch comprises a relatively small insulating member having mounted therein a movable blade, the insulating member being capable of being directly attached to the binding post on the top oi a spark plug. Several of these switches may be combined inv a composite testing device adapted to be located on the dash-board of an automobile or the like.

These and other features of the invention will be understood more clearly from the following specilication, taken with the accompanying drawings, in which ycertain embodiments are illustrated.

In the drawings- Figure 1 shows the improved testing switch mounted in position on an engine cylinder with the circuit of the spark plug represented diagrammatically;

Fig-..2 shows an enlarged side eleva-tion ot the spark plug andthe testing switch;

Fig. 3 shows a sectional view taken on the line Sw?) of Fig. 2; i

Fig. 4L shows a side elevation of a modified `form ofthe invention in which several I group on usual nuts 13 between which the electric conductor oii'the ignition circuit is ordinarily connected. In Fig. 1 this conductor 14 is shown extending to a battery or other source of electric current 15,'the other terminal of which is connected to a-conductor 16 leading to the ,engine frame orrot'h'er suitable part of the construction, whereby a return circuit to the other terminal ot the spark plug is formed Instead ot connecting the conductor 14 directly to the binding post 12, the present invention makes use of anintermediate testing switch designatedA generally by the numeral 18. This switch comprises an insulating base 19 formed preferably of insulating bre or the like and having a circular shape with a central circular aperture 2O extending therethrough. The lower portion of the ring shaped insulating base 19 is provided with a threaded aperture 21 which is adapted to engage the threaded binding post 12,*the binding post 12'extending upwardly intol the aperture 20. A slot 22 extends downwardly from the upper part of the insulating base, and this slot is adapted to contain a switch blade 23 of conducting material having an insulating handle 23a. rIhe upper edge of the blade is .preferably shaped to conform to the contour of the insulating base when the switch is closed, and the lower edge of theA kblade extends into the aperture 20 and is adapted to engage the upper end of the binding post 12. The blade is pivotally mounted on a bolt or screw 24; which is adapted to be engaged by the nuts 25 and 26 between which the conductor 14k is adapted to be clamped. lhen the switch is closed, the electric current passes from the conduc- 'tor 111- throughtheiswitch blade 23 to the binding post 12, which leads to one terminal ofthe spark gap. The blade ot the switch closely lits the slot 22 and is held in any desired adjusted position by the frictional contact of the walls of the slot.

In the operation of the invention, one of the switches 18 is'mountedon each spark plug carried by a cylinder of the engine, and these switches are normally `closed to complete the electric circuit for each cylinder.

If any cylinder is missing or for any otherreason itis desired to test the sparks `in the various cylinders, the switches 23 may be elevated separately or inV groups, and as eachswitch is opened, the spark passing between the lower edge of the blade and the e., Ha

upper end of the adjacent binding post 12 Till indicate whether a circuit is passing through the gap oi' the spark plug or whether the circuit is otherwise defective. By regulating the amount of opening of the switch, the strength of the spark produced by the plug can be determined.

Instead of mounting individual switches 18 on the several cylinders beneath the hood of the automobile, for example, the switches may be vformed n a group, as illustrated in Figs. l and 5. In this embodiment a single insulating base 30 of rectangular cross-section is provided with a longitudinally eX tending slot 31 which extends downwardly from the upper side thereof and completely through the insulating base .from end to end. A series of circular apertures 32 extend transversely through the base 30 with their lower walls in alinement with the lower wall of the slot 31. K Switch blades 33 of conducting material are mounted in the slot 31 and provided with insulating handles 33 by which they may be opened and closed. rIhe switch blades 33 are of angular 'form and are pivoted on bolts or screws 35 which extend through the insulating base. between the holes 32. The projecting ends of the screws 35 are engaged by nuts 36 and 37 be tween which the respective conductors 14 are adapted to be clamped. A pair of spring switch blades or plates 38 of conducting ma terial extend upwardly into each of the aperformed through the lower wall of the insulating base. 'Ihese switch blades are provided with angularly disposed arms which are held in position with respect to the base by screws L10. Y These screws 40 serve also to secure the conductors 145l in electrical connection with the blades 38. The conductors 14 lead to the binding posts 12 of the spark plugs, so that one oi' the switches 33 is included in circuit with each of the spark plugs of the engine. The blades 33 are normally in the position shown in Fig. Ll, but when it is desired to test any ot the plugs, they may be tilted upwardly in order to open any `desired switch, thereby determining whether a current is passing through the circuit kot each switch plug. In each form of the invention, the slots which are cut in the fibre insulating base are preferably narrow and adapted to cause a tight frictional engage ment with the lateral faces of the switch blades, so that the switches are normally held in closed positions by the trictional engagement ot the switch blades with the contacting insulating walls. The 'form of the invention illustrated in Figs. l and 5 has the advantage that it may be mounted on the dash-board of the automobile, thereby permitting the driver to test the circuits of the engine cylinders without leaving his se at.

Although certain. embodiments of the invention have been shown and described for 'purposes of illustration, it will be understood that the improvement may be constructed in variousdifferent forms without departing from the scope of the appended claims.

What I claim. is: l

1. The combination in a switch of a metallic terminal, an insulating member connectedto said terminal and having a slot therein, and a movable switch blade carried by said insulating member and movable into `said slot to enoao'e said metallic terminal.

minal, of an insulating member of circular form mounted on said terminal, said insulating memberhaving an aperture,therethrough and being slotted transverselyto said aper ture, a switch blade mounted in said slot and adapted `to engage said terminal within said aperture, and means for connectingl said `blade in a circuit. tures 33 through suitable holes 39 which are et. The combination with n, threadedbinding post, of a ring-shaped insulating member provided with a threaded aperture through one side thereof adapted to engage said binding post, said bindingpost being adapted to project into the central aperture oit said insulating member, said insulating member being slotted transversely to its central aperture, a switch blade movably mounted in and closely itting said slotvsaid blade being adapted to engage said post "and means ior connecting said blades in a circuit.

The combination with a threaded terminal, oil a ring-shaped insulating member providedwith a threaded. aperture` through 'one side thereof adapted to engage said terminal, said terminal being adapted to project into the central aperture of said. insulating member, said insulating member being slotted transversely to its central aperture, a switch blade mounted in and closely fitting said slot,v and adapted to engage said terminal, a connecting` member extending through said insulating member and having said switch blade pivotally mounted thereon, and means for forming an electrical connection with said connecting-member.

1n testimony whereof, I havesubscribed my name.

WILLIAM r. MoTT. 

